Gastrointestinal Nematode Parasites Research Articles

Understanding Animal-Plant-Parasite Interactions to Improve the Management of Gastrointestinal Nematodes in Grazing Ruminants.

Grazing systems have great potential to promote animal welfare by allowing animals to express natural behaviours, but they also present risks to the animals. Diseases caused by gastrointestinal nematodes are some of the most important causes of poor ruminant health and welfare in grazing systems and cause important economic losses. Reduced growth, health, reproduction and fitness, and negative affective states that indicate suffering are some of the negative effects on welfare in animals infected by gastrointestinal nematode parasitism. Conventional forms of control are based on anthelmintics, but their growing inefficiency due to resistance to many drugs, their potential for contamination of soil and products, and negative public opinion indicate an urgency to seek alternatives. We can learn to deal with these challenges by observing biological aspects of the parasite and the host's behaviour to develop managements that have a multidimensional view that vary in time and space. Improving animal welfare in the context of the parasitic challenge in grazing systems should be seen as a priority to ensure the sustainability of livestock production. Among the measures to control gastrointestinal nematodes and increase animal welfare in grazing systems are the management and decontamination of pastures, offering multispecies pastures, and grazing strategies such as co-grazing with other species that have different grazing behaviours, rotational grazing with short grazing periods, and improved nutrition. Genetic selection to improve herd or flock parasite resistance to gastrointestinal nematode infection may also be incorporated into a holistic control plan, aiming at a substantial reduction in the use of anthelmintics and endectocides to make grazing systems more sustainable.

Metagenome reveals caprine abomasal microbiota diversity at early and late stages of Haemonchus contortus infection

Haemonchus contortus is one of the most detrimental gastrointestinal nematode parasites for small ruminants, especially in tropics and subtropics. Gastrointestinal nematode and microbiota share the same microhabitat; thus they interact with each other and their host. Metagenomics tools provide a promising way to examine the alterations in the gastric microbial composition induces by gastrointestinal parasites. In this study, we used metagenomics tools to characterize the impact of H. contortus infection on the caprine abomasal microbiota at early and late stage of infection and compared it with non-infected control. Our results showed that H. contortus infection caused a significant increase in abomasal pH at early (7 days post-infection) and late stage of infection (56 days post-infection). The analysis of alpha and beta diversity showed that the microbiota diversity both in number and in proportion was significantly affected at early and late stage of infection. All microbiota classes are impacted by H. contortus infection but Clostridia and Bacteroidia are more concerned. In infected animals, the genera Prevotella decreased at 7 and 56 days post-infection. Here we showed that the abomasal microbiota was significantly affected early after H. contortus infection, and these changes persist at late stage of the infection.

Carbohydrate larval antigen (CarLA IgA) responses to mixed species nematode infection in pasture grazed Angora goats

The genetics of indicator traits for resistance of Angora goats to gastrointestinal nematode parasite infections, and their relationships with productivity traits, were investigated on a commercial mixed-enterprise farm in the eastern North Island of New Zealand. Faecal egg counts (FEC), specific Immunoglobulin A (IgA) and Immunoglobulin G (IgG) antibody titres against carbohydrate larval antigen (CarLA) in saliva, live weight and fleece weights were recorded from 278 goats of 19–20 months of age, run as four separate mobs (breeding bucks, castrated males (wethers), or 2 groups of breeding does). Summary statistics showed the mobs differed significantly in liveweight, loge (FEC+50), loge (IgA) and loge (IgG). Genetic parameters were estimated using an animal model with repeated records where appropriate, after adjusting for the different contemporary animal groups, using the restricted maximum likelihood (REML) package. Heritability estimates from repeated measures were 0.19 ± 0.16 for FEC, 0.28 ± 0.16 for CarLA specific IgA and 0.23 ± 0.15 for CarLA specific IgG. The CarLA specific IgA response was negatively genetically correlated with FEC (−0.99 ± 0.31) suggesting that it could be used as a selection tool for breeding resistant animals. Although the genetic and phenotypic correlations between CarLA IgA and IgG were high and significant, the analysis between loge (FEC+50) and loge CarLA IgG did not converge. Further, both FEC and CarLA IgA showed significant and favourable genetic correlations with live weight. In contrast, CarLA IgG showed an unfavourable phenotypic correlation with liveweight. While this is only a preliminary study, the results do suggest that the immunoassay measuring salivary CarLA IgA response may have utility as a selection tool for parasite resistance in some breeds of goats.

Faecal metabarcoding provides improved detection and taxonomic resolution for non-invasive monitoring of gastrointestinal nematode parasites in wild moose populations

BackgroundAlthough wild ungulate populations are heavily monitored throughout Europe, we understand little of how parasites affect population dynamics, and there is no systematic, long-term monitoring of parasite diversity and parasite loads. Such monitoring is in part hampered by a lack of time- and cost-effective assay methodologies with high sensitivity and good taxonomic resolution. DNA metabarcoding has been successfully used to characterize the parasitic nemabiome with high taxonomic resolution in a variety of wild and domestic hosts. However, in order to implement this technique in large-scale, potentially non-invasive monitoring of gastrointestinal parasitic nematodes (GIN), protocol optimization is required to maximize biodiversity detection, whilst maintaining time- and cost-effectiveness.MethodsFaecal samples were collected from a wild moose population and GIN communities were characterized and quantified using both parasitological techniques (egg and larva counting) and DNA metabarcoding of the ITS2 region of rDNA. Three different isolation methods were compared that differed in the volume of starting material and cell lysis method.ResultsSimilar nematode faunas were recovered from all samples using both parasitological and metabarcoding methods, and the approaches were largely congruent. However, metabarcoding assays showed better taxonomic resolution and slightly higher sensitivity than egg and larvae counts. The metabarcoding was not strictly quantitative, but the proportion of target nematode sequences recovered was correlated with the parasitologically determined parasite load. Species detection rates in the metabarcoding assays were maximized using a DNA isolation method that included mechanical cell disruption and maximized the starting material volume.ConclusionsDNA metabarcoding is a promising technique for the non-invasive, large-scale monitoring of parasitic GINs in wild ungulate populations, owing to its high taxonomic resolution, increased assay sensitivity, and time- and cost-effectiveness. Although metabarcoding is not a strictly quantitative method, it may nonetheless be possible to create a management- and conservation-relevant index for the host parasite load from this data. To optimize the detection rates and time- and cost-effectiveness of metabarcoding assays, we recommend choosing a DNA isolation method that involves mechanical cell disruption and maximizes the starting material volume.Graphical

The complete ITS2 barcoding region for Strongylus vulgaris and Strongylus edentatus

Gastrointestinal nematode parasites are of major concern for horses, where Strongylus vulgaris is considered the most pathogenic among the Strongylus species. Diagnosis of S. vulgaris infections can be determined with next generation sequencing techniques, which are inherently dependent on reference sequences. The best marker for parasitic nematodes is internal transcribed spacer 2 (ITS2) and we provide the first complete ITS2 sequences from five morphologically identified S. vulgaris and additional sequences from two S. edentatus. These sequences have high similarity to already published partial sequences and amplicon sequence variants (ASV) based on next generation sequencing (NGS). The ITS2 sequences from S. vulgaris matched available partial ITS2 sequences and the full ASVs, whereas the S. edentatus sequence matched another complete sequence. We also compare Sanger sequencing and NGS methods and conclude that the ITS2 variation is better represented with NGS methods. Based on this, we recommend that further sequencing of morphologically identified specimens of various species should be performed with NGS cover the intraspecific variation in the ITS2.

Influence of targeted selective anthelmintic treatment on the productive performance of wool and hair lambs naturally infected with gastrointestinal nematodes in Brazil.

Targeted selective treatment (TST) is an alternative method to reduce the use of anthelmintics and delay the development of resistant nematode populations. However, there is limited information on the actual effects of this type of treatment on livestock productivity. The objective of this study was to evaluate the production performance of Santa Ines (hair) and Ile de France (wool) lambs naturally infected with gastrointestinal nematodes (GIN) under TST based on packed cell volume (PCV) versus suppressive anthelmintic treatments. Thirty-eight lambs were divided into two treatment groups: Suppressive treatment, animals were drenched with monepantel every two weeks and TST, animals were treated with the same anthelmintic when they presented PCV ≤ 20%. Feces, blood, and weight were measured weekly to determine eggs per gram of feces, PCV, total plasma protein, and weight gain. After animals were slaughtered, carcasses were weighed to determine carcass yield. In the TST group, substantial productive losses of approximately 21.3% in the wool and 25.9% in the hair lambs were observed in body weight compared to their counterparts. Significant differences in hematological variables occurred over the experimental period, especially in the wool lambs under TST. Favorable environmental conditions enabled infective larvae to survive and thrive on pasture. Haemonchus contortus and intestinal nematodes were the most common parasites found in the Ile de France lambs and the Santa Ines lambs, respectively. Although TST prevented mortality, it did not prevent production losses. Both breeds showed a significant drop in production due to GIN parasitism.

Infecções por parasitas gastrintestinais em caprinos e ovinos de acordo com a variação sazonal no município de São Luís, estado do Maranhão, Brasil

ABSTRACT This study aimed to analyze the seasonal variation of gastrointestinal parasitic infections in goats and sheep in São Luís, Maranhão, Brazil. Fecal samples were collected directly from the rectal ampulla of the animals to count the eggs per gram in the feces at 30-day intervals over the 12-month study period. This study included 40 small ruminants, comprising 22 goats (14 sows, 6 kids, and 2 sires) and 18 sheep (13 sows, 4 lambs, and 1 sire). The study assessed the variation in the excretion of gastrointestinal nematode eggs during the dry and rainy seasons. Coproculture was performed to identify third-stage larvae. In the 12 months of research and monthly sample collections, 95.9% and 82.3% of the eggs detected were endoparasites in the fecal samples of the goats and sheep, respectively. Eimeria spp. oocysts were present in 50.6% and 30.4% of the goat and sheep fecal samples, respectively. The results indicated that the mean number of eggs per gram of feces was higher in the rainy season than in the dry season in both goats and sheep. The genera of gastrointestinal nematodes identified via monthly coproculture tests were Haemonchus sp., Trichostrongylus sp., and Oesophagostomum sp. Thus, gastrointestinal nematode parasitism was higher in goats and sheep during the rainy season than in the dry season, and the genera Haemonchus sp. and Trichostrongylus sp. were the most prevalent.

Trichostrongylosis: a zoonotic disease of small ruminants.

In the present world a significant threat to human health is posed by zoonotic diseases. Helminth parasites of ruminants are one of the most common zoonotic organisms on the planet. Among them, trichostrongylid nematodes of ruminants, found worldwide, parasitize humans in different parts of the world with varying rates of incidence, particularly among rural and tribal communities with poor hygiene, pastoral livelihood and poor access to health services. In the Trichostrongyloidea superfamily, Haemonchus contortus, Teladorsagia circumcincta, Marshallagia marshalli, Nematodirus abnormalis and Trichostrongylus spp. are zoonotic in nature. Species of the genus Trichostrongylus are the most prevalent gastrointestinal nematode parasites of ruminants that transmit to humans. This parasite is prevalent in pastoral communities around the world and causes gastrointestinal complications with hypereosinophilia which is typically treated with anthelmintic therapy. The scientific literature from 1938 to 2022 revealed the occasional incidence of trichostrongylosis throughout the world with abdominal complications and hypereosinophilia as the predominant manifestation in humans. The primary means of transmission of Trichostrongylus to humans was found to be close contact with small ruminants and food contaminated by their faeces. Studies revealed that conventional stool examination methods such as formalin-ethyl acetate concentration or Willi's technique combined with polymerase chain reaction-based approaches are important for the accurate diagnosis of human trichostrongylosis. This review further found that interleukin 33, immunoglobulin E, immunoglobulin G1, immunoglobulin G2, immunoglobulin M, histamine, leukotriene C4, 6-keto prostaglandin F1α, and thromboxane B2 are vital in the fight against Trichostrongylus infection with mast cells playing a key role. This review focuses on the prevalence, pathogenicity and immunological aspects of Trichostrongylus spp. in humans.

In Vitro Anthelmintic Activity of a Hydroalcoholic Extract from Guazuma ulmifolia Leaves against Haemonchus contortus.

The purpose of the present study was to assess the ovicidal and larvicidal activity of a hydroalcoholic extract (HAE) and their fractions (aqueous, Aq-F and organic, EtOAc-F) from Guazuma ulmifolia leaves using Haemonchus contortus as a biological model. The egg hatching inhibition (EHI) and larval mortality against infective larvae (L3) tests were used to determine the anthelmintic effect of the treatments. The extract and fractions were tested at different concentrations against eggs and L3. Additionally, distilled water and methanol were used as negative controls and ivermectin as a positive control. The extract and fractions were subjected to HPLC analysis to identify the major compounds. The HAE displayed the highest ovicidal activity (100% EHI at 10 mg/mL). Fractionation of the HA extract allowed increasing the nematicidal effect in the EtOAc-F (100% EHI at 0.62 mg/mL and 85.35% mortality at 25 mg/mL). The phytochemical analysis of the extract and fractions revealed the presence of kaempferol, ethyl ferulate, ethyl coumarate, flavonol, luteolin, ferulic acid, luteolin rhamnoside, apigenin rutinoside, coumaric acid derivative, luteolin glucoside, and quercetin glucoside. These results suggest that G. ulmifolia leaves could be potential candidates for the control of H. contortus or other gastrointestinal parasitic nematodes.

Generalist nematodes dominate the nemabiome of roe deer in sympatry with sheep at a regional level

The growth of livestock farming and the recent expansion of wild ungulate populations in Europe favor opportunities for direct and/or indirect cross-transmission of pathogens. Comparatively few studies have investigated the epidemiology of gastro-intestinal nematode parasites, an ubiquitous and important community of parasites of ungulates, at the wildlife/livestock interface. In this study, we aimed to assess the influence of livestock proximity on the gastrointestinal nematode community of roe deer in a rural landscape located in southern France. Using ITS-2 rDNA nemabiome metabarcoding on fecal larvae, we analysed the gastrointestinal nematode communities of roe deer and sheep. In addition, we investigated Haemonchus contortus nad4 mtDNA diversity to specifically test parasite circulation among domestic and wild host populations. The dominant gastrointestinal nematode species found in both the roe deer and sheep were generalist species commonly found in small ruminant livestock (e.g. H. contortus), whereas the more specialised wild cervid nematode species (e.g. Ostertagia leptospicularis) were only present at low frequencies. This is in marked contrast with previous studies that found the nemabiomes of wild cervid populations to be dominated by cervid specialist nematode species. In addition, the lack of genetic structure of the nad4 mtDNA of H. contortus populations between host species suggests circulation of gastrointestinal nematodes between roe deer and sheep. The risk of contact with livestock only has a small influence on the nemabiome of roe deer, suggesting the parasite population of roe deer has been displaced by generalist livestock parasites due to many decades of sheep farming, not only for deer grazing close to pastures, but also at a larger regional scale. We also observed some seasonal variation in the nemabiome composition of roe deer. Overall, our results demonstrate significant exchange of gastrointestinal nematodes between domestic and wild ungulates, with generalist species spilling over from domestic ungulates dominating wild cervid parasite communities.

Tracking gastrointestinal nematode risk on cattle farms through pasture contamination mapping

Gastrointestinal nematode (GIN) parasites in grazing cattle are a major cause of production loss and their control is increasingly difficult due to anthelmintic resistance and climate change. Rotational grazing can support control and decrease reliance on chemical intervention, but is often complex due to the need to track grazing periods and infection levels, and the effect of weather on larval availability. In this paper, a simulation model was developed to predict the availability of infective larvae of the bovine GIN, Ostertagia ostertagi, at the level of individual pastures. The model was applied within a complex rotational grazing system and successfully reproduced observed variation in larval density between fields and over time. Four groups of cattle in their second grazing season (n = 44) were followed throughout the temperate grazing season with regular assessment of GIN faecal egg counts, which were dominated by O. ostertagi, animal weight and recording of field rotations. Each group of cattle was rotationally grazed on six group-specific fields throughout the 2019 grazing season. Maps and calendars were produced to illustrate the change in pasture infectivity (density of L3 on herbage) across the 24 separate grazing fields. Simulations predicted differences in pasture contamination levels in relation to the timing of grazing and the return period. A proportion of L3 was predicted to persist on herbage over winter, declining to similar intensities across fields before the start of the following grazing season, irrespective of contamination levels in the previous year. Model predictions showed good agreement with pasture larval counts. The model also simulated differences in seasonal pasture infectivity under rotational grazing in systems that differed in temperature and rainfall profiles. Further application could support individual farm decisions on evasive grazing and refugia management, and improved regional evaluation of optimal grazing strategies for parasite control. The integration of weather and livestock movement is inherent to the model, and facilitates consideration of climate change adaptation through improved disease control.

Untargeted Multimodal Metabolomics Investigation of the Haemonchus contortus Exsheathment Secretome.

In nematodes that invade the gastro-intestinal tract of the ruminant, the process of larval exsheathment marks the transition from the free-living to the parasitic stages of these parasites. To investigate the secretome associated with larval exsheathment, a closed in vitro system that effectively reproduces the two basic components of an anaerobic rumen environment (CO2 and 39 °C) was developed to trigger exsheathment in one of the most pathogenic and model gastrointestinal parasitic nematodes, Haemonchus contortus (barber‘s pole worm). This study reports the use of multimodal untargeted metabolomics and lipidomics methodologies to identify the metabolic signatures and compounds secreted during in vitro larval exsheathment in the H. contortus infective third-stage larva (iL3). A combination of statistical and chemoinformatic analyses using three analytical platforms revealed a panel of metabolites detected post exsheathment and associated with amino acids, purines, as well as select organic compounds. The major lipid classes identified by the non-targeted lipidomics method applied were lysophosphatidylglycerols, diglycerides, fatty acyls, glycerophospholipids, and a triglyceride. The identified metabolites may serve as metabolic signatures to improve tractability of parasitic nematodes for characterizing small molecule host–parasite interactions related to pathogenesis, vaccine and drug design, as well as the discovery of metabolic biomarkers.

Prevalence of gastrointestinal helminths of small ruminants subjected to traditional livestock management system in Gadau district, Bauchi state Nigeria

Globally, parasitic diseases are one of serious concerns in production and management of livestock. African climate and other environmental factors constitute a favorable condition for the growth of gastrointestinal parasites in animals. This research work was aimed at assessment of prevalence of parasites infesting gastrointestinal tracks of goats and sheep at Gadau District, Northern Nigeria. The results reveal the overall prevalence of 42.7% gastrointestinal parasites in both goats and sheep in the study area. It indicates that sheep were less infected with gastrointestinal parasitic nematodes than the goats. It also revealed that the degree of incidence of gastrointestinal parasitic nematodes infection varies among the age, sex and species of small ruminants in the study area, due to the management system for the small ruminants.

Development of Bovine Gastric Organoids as a Novel In Vitro Model to Study Host-Parasite Interactions in Gastrointestinal Nematode Infections.

Gastro-intestinal nematode (GIN) parasites are a major cause of production losses in grazing cattle, primarily through reduced growth rates in young animals. Control of these parasites relies heavily on anthelmintic drugs; however, with growing reports of resistance to currently available anthelmintics, alternative methods of control are required. A major hurdle in this work has been the lack of physiologically relevant in vitro infection models that has made studying precise interactions between the host and the GINs difficult. Such mechanistic insights into the infection process will be valuable for the development of novel targets for drugs, vaccines, or other interventions. Here we created bovine gastric epithelial organoids from abomasal gastric tissue and studied their application as in vitro models for understanding host invasion by GIN parasites. Transcriptomic analysis of gastric organoids across multiple passages and the corresponding abomasal tissue showed conserved expression of tissue-specific genes across samples, demonstrating that the organoids are representative of bovine gastric tissue from which they were derived. We also show that self-renewing and self-organising three-dimensional organoids can also be serially passaged, cryopreserved, and resuscitated. Using Ostertagia ostertagi, the most pathogenic gastric parasite in cattle in temperate regions, we show that cattle gastric organoids are biologically relevant models for studying GIN invasion in the bovine abomasum. Within 24 h of exposure, exsheathed larvae rapidly and repeatedly infiltrated the lumen of the organoids. Prior to invasion by the parasites, the abomasal organoids rapidly expanded, developing a ‘ballooning’ phenotype. Ballooning of the organoids could also be induced in response to exposure to parasite excretory/secretory products. In summary, we demonstrate the power of using abomasal organoids as a physiologically relevant in vitro model system to study interactions of O. ostertagi and other GIN with bovine gastrointestinal epithelium.

Expression and Secretion of Circular RNAs in the Parasitic Nematode, Ascaris suum.

Circular RNAs (circRNAs) are a recently identified RNA species with emerging functional roles as microRNA (miRNA) and protein sponges, regulators of gene transcription and translation, and modulators of fundamental biological processes including immunoregulation. Relevant to this study, circRNAs have recently been described in the parasitic nematode, Haemonchus contortus, suggesting they may have functionally important roles in parasites. Given their involvement in regulating biological processes, a better understanding of their role in parasites could be leveraged for future control efforts. Here, we report the use of next-generation sequencing to identify 1,997 distinct circRNAs expressed in adult female stages of the gastrointestinal parasitic nematode, Ascaris suum. We describe spatial expression in the ovary-enriched and body wall muscle, and also report circRNA presence in extracellular vesicles (EVs) secreted by the parasite into the external environment. Further, we used an in-silico approach to predict that a subset of Ascaris circRNAs bind both endogenous parasite miRNAs as well as human host miRNAs, suggesting they could be functional as both endogenous and exogenous miRNA sponges to alter gene expression. There was not a strong correlation between Ascaris circRNA length and endogenous miRNA interactions, indicating Ascaris circRNAs are enriched for Ascaris miRNA binding sites, but that human miRNAs were predicted form a more thermodynamically stable bond with Ascaris circRNAs. These results suggest that secreted circRNAs could be interacting with host miRNAs at the host-parasite interface and influencing host gene transcription. Lastly, although we have previously found that therapeutically relevant concentrations of the anthelmintic drug ivermectin inhibited EV release from parasitic nematodes, we did not observe a direct effect of ivermectin treatment on Ascaris circRNAs expression or secretion.

Study on Gastrointestinal Nematodes of Equines in and around Bekoji, South Eastern Ethiopia.

Parasitic infections can cause a variety of respiratory, intestinal, and other problems in horses, as well as contribute to some performance issues. A cross-sectional study was undertaken in and around Bekoji, South Eastern Ethiopia, from November 2020 to June 2021 to identify species and evaluate the prevalence of gastrointestinal parasites in donkeys and horses, using direct fecal smear, floatation methods, and larval cultures. In this study, the overall prevalence of gastrointestinal nematode parasites was 94.5% (363 out of 384), with donkeys accounting for 95.8% and horses accounting for 90.5%. The coprological study indicated that an overall prevalence of gastrointestinal nematode parasites was 87%, 8.3%, 2.5%, 1.4%, and 0.8% for mixed parasite infection, nonmigratory strongylids, migratory strongylids, Parascaris equorum, and Oxyuris equi, respectively. Among mixed infections, nonmigratory strongylids+migratory strongylids (51.5%) occurred most frequently. The odds of male horses being infected by GIT nematodes were 1.59 times higher than male donkeys. Horses which have poor body condition were 2.94 times more infected than donkeys. The odds of old-aged donkeys were 3.11 times more infected than horses. A statistically significant difference (p < 0.05) was observed in the prevalence of gastrointestinal nematodes with species and body conditions of the animals. However, no statistically significant difference (p > 0.05) was seen in the prevalence of gastrointestinal nematode parasites between the sex and age of the Equidae. The mean fecal egg count of nematodes revealed that horses (1364.4 ± 483.5) had a more severe infection than donkeys with a statistically significant difference (p < 0.05). The current study determined there was a high prevalence of gastrointestinal nematode parasites in Equidae. Regular deworming, improved housing and nutrition management systems, increased animal owner awareness, and prevention techniques should all be undertaken to minimize the disease's economic burden in the area.

Comparative study of the effects of albendazole and annual mug wort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Nowadays, cattle breeding is a major economic issue throughout the world. However, gastrointestinal nematode parasitism remains a major sanitary threat on a global scale, affecting animal health, farm productivity and the well-being of farmers. Until recently, chemical anthelmintics occupied a prominent place in the fight against these parasites. But some of them have developed resistance to antiparasitic drugs. The objective of this study is to compare the anthelmintic effects of commercial albendazole (8.3 mg/kg body weight) and annual mugwort (Artemesia annua, 100 mg and 150 mg) powder on gastrointestinal roundworms in cattle. Lots of animals were formed in a population of 92 animals, and underwent different treatments: with albendazole and with annual mugwort powder. The results showed that the artemesia annua powder has a strong inhibition on the nematodes but failed to eliminate them completely. Albendazole, for its part, showed a very effective effect with a 100% elimination of nematodes. These results highlight the possibility of using annual mugwort as an alternative to albendazole on farms.

Monacrosporium sinense and Pochonia chlamydosporia for the biological control of bovine infective larvae in Brachiaria brizantha pasture

Ecologically correct solutions are necessary to minimize the use of anthelmintics in the control of cattle parasitic diseases. This study evaluated the effects of oral administration pellets containing the fungal combination Monacrosporium sinense and Pochonia chlamydosporia in the biological control of infective larvae (L3) of parasitic gastrointestinal nematodes of cattle grazed in pasture. Twelve crossbred bovines (Holstein × Zebu), seven to nine years old, after dewormed, were randomly divided into two groups (group treated with the combination of fungi and control group) and placed in separate paddocks of Brachiaria brizantha that were naturally infested with L3. Feces samples were collected from the animals to determine the parasitic load and pasture samples were collected from the soil to determine the L3 infestation. The recovery of L3 from the pasture of the treated group was 91.7% and 86.4% less than in the pasture of the control group, respectively for samples collected at 20 cm and 40 cm from the faecal pats. The values of eggs per gram of feces in the months of May 2019 and January 2020 were lower (p ≤ 0.05) in the treated group with the fungal combination. The combined administration of M. sinense and P. chlamydosporia reduced the L3 infestation on pasture and in animal parasitic load, making it a tool for controlling bovine gastrointestinal parasitic nematodes.

Naturally acquired ovine-adapted nematode infections in young cattle and their treatment with eprinomectin 5% w/v extended-release injection.

The objective of this controlled study was to determine the anthelmintic efficacy of eprinomectin 5% w/v extended-release injection (Eprinomectin ERI; LONGRANGE®, Boehringer Ingelheim Animal Health) against primarily ovine-adapted gastrointestinal strongylid nematode (GIN) parasites in naturally infected young cattle. Eighteen calves which grazed on a sheep-dominated mixed sheep-cattle farm were randomly allocated into two equal groups (saline [control] or Eprinomectin ERI, administered each at 1mL/50kg body weight once subcutaneously), treated and euthanized 14days thereafter for a differential GIN count. Ten species of strongylid nematodes were recovered from the control calves (ovine-adapted Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis, Cooperia curticei, Nematodirus battus, Chabertia ovina; bovine-adapted Ostertagia ostertagi, Cooperia oncophora, Nematodirus helvetianus; 'generalist' Trichostrongylus axei). Adult GIN counts ranged from 1,540 to 5,244 for the control calves and from zero to 110 for the Eprinomectin ERI-treated calves. Accepting the International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products anthelmintic guidelines criteria on adequacy of infections to be demonstrated in the control animals, this study showed that Ch. ovina, C. curticei, H. contortus, N. battus, T. axei, and T. colubriformis were reduced significantly (p < 0.0001) by ≥ 98.7% in the animals treated with Eprinomectin ERI. In conclusion, Eprinomectin ERI treatment was efficacious against a range of ovine-adapted nematode parasites in naturally infected young cattle.

Assessing Goats' Fecal Avoidance Using Image Analysis-Based Monitoring

The recent advances in sensor technologies and data analysis could improve our capacity to acquire long-term and individual dataset on animal behavior. In livestock management, this is particularly interesting when behavioral data could be linked to production performances, physiological or genetical information, with the objective of improving animal health and welfare management. In this study, we proposed a framework, based on computer vision and deep learning, to automatically estimate animal location within pasture and discuss the relationship with the risk of gastrointestinal nematode (GIN) infection. We illustrated our framework for the monitoring of goats allowed to graze an experimental plot, where feces containing GIN infective larvae were previously dropped in delimited areas. Four animals were monitored, during two grazing weeks on the same pasture (week 1 from April 12 to 19, 2021 and week 2, from June 28 to July 5, 2021). Using the monitoring framework, different components of animal behavior were analyzed, and the relationship with the risk of GIN infection was explored. First, in average, 87.95% of the goats were detected, the detected individuals were identified with an average sensitivity of 94.9%, and an average precision of 94.8%. Second, the monitoring of the ability of the animal to avoid infected feces on pasture showed an important temporal and individual variability. Interestingly, the avoidance behavior of 3 animals increased during the second grazing week (Wilcoxon rank sum, p-value &amp;lt; 0.05), and the level of increase was correlated with the level of infection during week 1 (Pearson's correlation coefficient = 0.9). The relationship between the time spent on GIN-infested areas and the level of infection was also studied, but no clear relationship was found. In conclusion, due to the low number of studied animals, biological results should be interpreted with caution; nevertheless, the framework provided here is a new relevant tool to explore the relationship between ruminant behavior and GIN parasitism in experimental studies.